1. Technical Field
The present invention relates to an apparatus and a method for cutting a web member that has a plurality of fibers including tows.
2. Related Art
A conventional cleaning web member is known into which a handle member is inserted to make the web member usable for cleaning of a tabletop and the like (JP 2005-40641A). Such a cleaning web member has a main body in which a plurality of fibers are layered on a base sheet. As the fibers, used are continuous fibers made of a thermoplastic resin, called tows.
In the production line of the cleaning web member, a plurality of tows whose fiber direction is in a predetermined direction are secured by means such as welding to a base sheet that is continuous along the predetermined direction. Thus, a web member that is continuous in the predetermined direction is formed as a semi-finished product. Finally, this web member is cut along a width direction that intersects the predetermined direction so that single-cut cleaning web members are manufactured.
As a method for cutting this web member, the cutting apparatus disclosed in JP 2011-62802A can be considered. That is to say, the web member is cut by passing the web member through a space between a cutter roll and an anvil roll and pressing the web member between the cutter blade and the receiver blade. The cutter roll has an outer circumferential face having a cutter blade, and the anvil roll has a receiver blade that receives the cutter blade.
However, the tows used in the web member are thermoplastic ones. Therefore, tows are attached at the target cut position by welding or compression-bonding because the web member is pressed between the cutter blade and the receiver blade during cutting. This may cause a trouble that the cut edges is bound to each other in loops, which results in deterioration of the performance of the brush section (dust trapping performance during cleaning).
Furthermore, if the cut edges are bound to each other in loops, bulkiness of the cleaning web member decreases, which also lowers the performance of the brush section.
Furthermore, due to contact of the cutter blade with the receiver blade during cutting, the cutting edge of the cutter blade is likely to be worn, which shortens the life of the cutter blade.
As a method in a reference example that can solve these problems, it is conceivable that the web member is cut as follows: a rotatable blade is used whose cutting edge in the outer circumferential edge portion has a plurality of recess portions; a rotatable blade is moved in the width direction of the web member while being driven and rotated about a rotation shaft along the predetermined direction; and thereby the web member is cut. With this method, a high cutting performance is achieved by driving and rotating the rotatable blade. In addition, the cutting is facilitated by causing tows to be caught on the recess portions. Thus, the cutting can be reliably performed simply by bringing the rotatable blade into contact with the web member. The rotatable blade does not require a receiver blade against which the web member is pressed during cutting. This can reliably prevent tows from being attached at a target cut position by welding or compression-bonding, which may occur during pressing. Furthermore, since the cutting edge of the rotatable blade is brought into contact only with the web member during cutting. This can suppress wear of the rotatable blade.
Furthermore, with the above-described cutting method using the rotatable blade, cut fibers such as tows are in contact with the blade faces of the disc-like rotatable blade throughout a period from when cutting of the fibers is just started to when the web member is completely cut by the rotatable blade. Due to rotation of the blade faces, the cut fibers are spread and loosened in directions such as the thickness direction of the web member. Thus, fibers near a cut position in the web member can become very soft and bulky. This can achieve high bulkiness of the single-cut product of the web member formed by cutting, that is, the cleaning web member.
However, depending on the size of the recess portions in the outer circumferential edge portion of the rotatable blade, the tows easily enter into the recess portions. If the tows enter into the recess portions, molten residue of the tows easily adheres to portions near the recess portions and is accumulated on the cutting edge. As a result, the cutting performance (cutting capability) of the rotatable blade is lowered. Accordingly, molten residue has to be regularly removed from the cutting edge, which results in low productivity.